1. Field of the Invention
This invention relates to a foam-producing device.
2. The Related Art
Certain known types of foam producing devices are disclosed in U.S. Pat. No. 4,147,306 and U.S. Pat. No. 4,156,505 both issued to Bennett. These employ a deformable reservoir of foamable fluid and air, a discharge device and a foam producing device which include both a foam overlay or filter and a ball check valve. The foam-producing device has a well with air passages, which form a mixing chamber. When the reservoir is squeezed, the liquid and air are mixed in the chamber. The mixture is passed through the overlay to produce foam which is discharged through the orifice. The check valve is disposed in the path of liquid flow and is opened by the squeezing action and is closed when the pressure is released. The valve, when closed, prevents downward flow of liquid or foam which otherwise could clog or jam the dispenser. However, such arrangements suffer from certain other disadvantages.
For example, prior art devices have multiple parts which are costly to manufacture in quantity. Moreover, many of the prior art devices require a long time to recharge air that has been discharged from the container when foam has been produced. Accordingly, one aspect of the present invention is to provide a foam nozzle and dispenser at least as efficient as earlier devices, yet manufactured with fewer parts thereby saving some assembly cost and reducing complexity. Another aspect of the present invention is to provide a foam dispenser which rapidly recharges air between discharges of foam.
In the present invention, the disadvantages of prior foam nozzles and dispensers have been found to be overcome by using a shaped resilient seal which allows the container to recharge with air in a much more efficient manner. A swirl manifold is also advantageously employed to create good quality foam and, in a preferred arrangement, is cast as an integral component in the foam-generation housing of the instant invention. The inventive foam dispenser uses fewer parts and can be more easily assembled and, therefore, can be produced and sold at a much lower cost.
In one aspect of the invention, a nozzle for dispensing foam is provided including a foam generation housing; a mixing conduit with an outlet and an inlet disposed in the foam generation housing for blending fluid and vapor to generate foam, a plurality of spaced apart mesh screens for creating turbulence zones disposed in the mixing conduit adjacent to the outlet; and a swirl manifold fluidly communicating with the inlet and disposed downstream from the plurality of spaced apart mesh screens for contacting the fluid with vapor to create a swirling fluid and vapor flow pattern. The swirl manifold has a surface, and defines an aperture communicating with the mixing conduit inlet and the fluid conduit outlet. The manifold surface also has at least one swirl conduit in communication with the aperture and the vapor conduit outlet; wherein the vapor flows through the swirl conduit and enters the aperture tangentially.
The inventive nozzle preferably includes a fluid conduit and a vapor conduit each having an outlet and an inlet; and a vent; each disposed in the foam generation housing. The plurality of screens preferably includes a first screen, and a second screen disposed downstream from the first screen. Preferably, the nozzle also includes a foam conduit housing containing a foam conduit for transporting foam created in the mixing conduit, which communicates with the mixing conduit outlet; and an adapter fixedly connected to the foam conduit housing. Preferably the adapter is slidably coupled to an outer surface of the foam generation housing for movement between an open and a closed position, the open position allowing communication between the atmosphere and the fluid and vapor in a container and the closed position preventing communication between the atmosphere and the fluid and vapor in the container.
Preferably the inventive nozzle""s foam conduit housing has a sealing projection and at least one detent positioned to engage the outer surface of the foam generation housing when the foam conduit housing is moved between the closed and the open position. Preferably the inventive nozzle further includes a check valve disposed in the mixing conduit for preventing the back flow of fluid and foam into the container.
Advantageously, the inventive nozzle has its swirl manifold integrally formed with the foam generation housing, and the manifold has a central aperture and the manifold surface has a plurality of etched swirl conduits tangentially communicating with the aperture, each of the swirl conduits having a major axis. Preferably the number of swirl conduits etched in the swirl manifold surface is in the range of 2 to about 50. More preferably the number of swirl conduits are at least two and the major axis of at least one swirl conduit is disposed at right angles to a major axis of a second swirl conduit.
In another aspect of the invention is a nozzle for dispensing foam, including a foam generation housing having a vent; a mixing conduit disposed in the foam generation housing for blending fluid and vapor to generate foam, the mixing conduit having an outlet and an inlet; a plurality of spaced apart mesh screens for creating turbulence zones disposed in the mixing conduit adjacent to the outlet; and a flared deformable vent seal for allowing the ingress of air into the container via the vent, the seal being disposed and movably engaged within the foam generation housing for movement between an open position allowing air ingress and a closed position when foam is discharged. In the context of the present invention, the flared character of the deformable vent seal is defined by the seal meeting a cylinder outer wall at an angle of less than 75 degrees in contrast to a flat seal which would meet the outer wall at an angle near 90 degrees.
Preferably the inventive nozzle""s vent seal has a top wide end, a radially projecting flange connected to the wide end, and a narrow bottom end defining a seal aperture. The flange is in sealing engagement with a lower surface of the foam generation housing, and the seal bottom end is in sealing engagement with the cylinder outer wall of the foam generation housing.
Preferably the vent seal engages the cylinder outer wall at an angle defined by the seal and the cylinder outer wall in the range of about 35 to about 55 degrees, whereby negative pressure in the container causes the seal to move away from the outer wall allowing the egress air in the container. More preferably, the vent seal is conical in shape.
Advantageously, the inventive nozzle has an annular resiliently deformable ring concentrically disposed outside the mixing conduit and adapted to engage the vent seal and configured for movement between an open position and a closed position similar to a crab""s claw. The open position for engaging at least a portion of the first resilently deformable seal, and the closed position for pressing the vent seal to the lower surface of the foam generation housing. More preferably, the annular resiliently deformable seal is integrally cast within the foam generation housing adjacent to the lower surface to reduce production costs.
In another aspect of the invention, the inventive nozzle is combined with a container to provide a foam dispenser. The container is coupled to the foam generation housing by the neck. The container will typically have threads, dimples, or the like to engage the nozzle. The nozzle will have complementary threads, depressions, or the like molded on an outer surface so as to engage the container and the annular resiliently deformable seal will then move to the closed position when the foam generation housing sealingly engages the container. Preferably the container threadably engages the foam generation housing.
In this aspect of the present invention, foam is dispensed by increasing the pressure in the container by any suitable means. Preferably the container is composed of a flexible polymeric material and the foam is dispensed by increasing the pressure in the container by deforming the container such as by squeezing by hand, using a bellows or pump device or source of pressurized gas, and the like. Preferably an external pumping device such as trigger pump commonly found in a trigger sprayer is not used. Such an external pumping device does not increase the pressure in the container. An example of such a trigger sprayer is described in U.S. Pat. No. 6,116,472 issued to Wanbaugh, et al. on Sep. 12, 2000.
In operation, the foam generation housing is secured to the open neck of a container of fluid, the fluid conduit inlet is extended into the container to a depth below the fluid level, and the vapor conduit inlet is extended into the vapor space of the container. When the nozzle in the open position and the container is squeezed or pressurized, the vent seal is forced closed sealing the vent. Vapor or air flows upwardly through the vapor conduit and the fluid flows upwardly through the fluid conduit. The fluid and air are mixed together in the swirl manifold disposed in the mixing conduit creating a vortex of fluid entrained with air. The fluid/air mixture passes through the check valve and the plurality of screens and is converted to foam. The foam flows through the foam conduit section of the nozzle and is discharged.
When the pressure is released, the vent seal opens and air is fed through the vent hole and passed the vent seal into the container to replace the air previously used to produce foam. After the pressure is equalized, the nozzle may be placed in the closed position. The dispenser is sealed and fluid cannot leak out even if the dispenser is tilted or inverted.